The perspective view of an ordinary oil stove is shown in FIG. 1 as an example of conventional burners. A reflector 2 is contained in a housing 1, and a burner unit in the form of a combustion cylinder 3 is arranged at the central part of the curved surface of the reflector 2. The combustion cylinder 3 in turn contains a wick by which oil (kerosene) sucked up by capillarity is burned. As a result, the combustion cylinder 3 is red heated, and heat thus generated provides radiation heat or reflection heat in front of the stove by way of the reflector 2 thereby to effect the heating operation. A knob 4 is provided for vertically moving the wick. When the knob 4 is moved upward, a button 5 is depressed to ignite the wick, thereby starting combustion. When the other knob 25 is depressed downward, the knob 4 is disengaged and is restored to the original position. At the same time, the wick in the combustion cylinder 3 lowers to thereby extinguish the fire.
The oil stove of this construction consumes oxygen in the working environment. If oxygen is in short supply, the oxygen concentration decreases slowly so that the lack of oxygen occurs in the combustion cylinder 3 while carbon monoxide increases in amount.
In such a situation, the human body is adversely affected and sufficient ventilation of the room is necessary. The user thus consciously opens the window at predetermined time intervals to take in fresh air. If the user fails to take in fresh air, however, the oxygen concentration is reduced while carbon monoxide increases to cause the dangerous condition called "the lack or shortage of oxygen".
In order to meet such a situation, an oil stove is required in which such a dangerous situation is detected and an alarm is issued by an illuminator 24 used as alarming or warning means or in which the combustion is automatically stopped by combustion stopper means. Such an oil stove is required to include an oxygen shortage sensor for detecting the decrease of oxygen concentration or the increase of carbon monoxide. Various types of oxygen shortage sensors are conceivable. Among them, the most desirable one detects oxygen concentration or oxygen partial pressure or carbon monoxide. Such a sensor detects the shortage of oxygen directly but not indirectly and has the great advantage of high reliability. Nevertheless, the oxygen shortage sensor is incapable of performing the function thereof unless maintained at higher than a predetermined temperature on the one hand and undesirably operates in response to temperature changes on the other hand. The characteristics of an oxygen shortage sensor are shown in FIGS. 2(a) and 2(b). In the case where the oxygen shortage sensor is made of tin oxide or the like, for example, the resistance value thereof changes with oxygen concentration as shown in FIG. 2(a) if the ambient temperature is maintained constant, while the resistance value still continues to change with the change of temperature even when the oxygen concentration is kept substantially constant as shown in FIG. 2(b). When the oil stove is provided with the oxygen shortage sensor, therefore, the ambient temperature is required to be maintained substantially constant. Otherwise, an alarm may be falsely issued or combustion may be stopped even when oxygen is not in short supply.